Dietary fat is one of the most concentrated sources of energy of all the nutrients, typically supplying about 9 kcal/gram, which generally exceeds the caloric content provided by either dietary carbohydrates or protein. Fat contributes to the palatability and flavor of food, since most food flavors are fat-soluble, and to the satiety value, since fatty foods remain in the stomach for longer periods of time than do foods principally containing protein and carbohydrate. Furthermore, fat is a carrier of the fat-soluble vitamins A, D, E, and K and essential fatty acids, which have been shown to be important in growth and in the maintenance of many body functions. Major research efforts have focused on ways to produce food substances that provide similar functional and organoleptic properties as fats at reduced caloric content but which are not readily perceived as being synthetic by consumers.
Natural fats have a broad range of functionalities and are handled in different ways by the human digestive process. A shortening is one type of fat that has a generally high solid fat content at room temperatures and desired melting profiles to provide a certain mouthfeel and organoleptic characteristics. However, such fats may also contain trans-unsaturated fatty acids or saturated fatty acids in forms that are digested and absorbed by the body. Such fatty acids have been linked in recent years to health concerns; however, such fats are generally necessary in the shortening to provide the desired solid fat content and melting profile.
Conventional fat and oil technology has traditionally relied on partial hydrogenation to impart a solid functionality to oils. However, this approach results in oils that contain significant levels of undesired trans-unsaturated fatty acids (TFA's). For example, to form the typical shortening, a liquid vegetable oil is partially hydrogenated to convert the oil into a form suitable for a shortening and produce the desired functionality (hardness and melting profiles suitable for the shortening). The partial hydrogenation, however, can also convert some unsaturated fatty acids in the oil from a cis-orientation to the undesired trans-orientation.
Data in recent years has linked trans-unsaturated fatty acids and some saturated fatty acids to a variety of health concerns. One such health concern, high cholesterol, may be caused, in part, by a diet that includes high levels of such fatty acids. For example, it is now generally accepted that consumption of trans-fatty acids contribute to increased LDL or “bad” cholesterol levels, which may increase the risk of coronary heart disease. Mounting evidence further suggests that, in some individuals, high cholesterol may contribute to increased risk of heart attacks, strokes, and other tissue injuries. There is a desire, therefore, to minimize the amount of trans-fatty acids in foods. Under FDA guidelines, a food or fat can be listed as having zero trans-fatty acids if it contains less than about 0.5 grams of trans-fatty acids per serving. To achieve such levels in a typical baked snack food product, such as a sandwich cookie, the trans-fatty acids in the particular ingredient oils must be kept well below about 3 to about 7 percent. Such levels present challenges in preparing functional shortenings and filler fats having sufficient solid fat content, and desirable organoleptic properties.
In recent years, many efforts have been made to reduce the fat content and the trans-fatty acid content of various foods. However, when the fat level and/or trans-fatty acid level is reduced in conventional foods, the organoleptic and/or functional properties may also be adversely affected. For example, by reducing the level of trans-fatty acids, the hardness and solid fat content is altered so that the fat does not exhibit the desired functionality. In other cases, by reducing the fat content to low levels, the oiliness and/or slipperiness (i.e., mouthfeel) imparted by the fat particles suspended in the food product are effectively lost. In addition, other mouthfeel and textural properties, such as richness and creaminess, may also be adversely affected by the removal or reduction of such fats. Furthermore, flavor properties may be adversely affected because the distribution of flavor molecules between the lipid phase and the aqueous phase is altered. As a result, such reduced-fat food products may not be appealing to the consumer because of their mouthfeel, flavor, and/or organoleptic properties.
U.S. Pat. Nos. 5,879,735 and 5,912,042 describe fat blends comprising diglycerides and triglycerides with long chain saturated and unsaturated fatty acids. The compositions of the '735 patent and the '042 patent, however, have relatively high amounts of fully saturated long chain fatty acids (C12-C24). Fully-saturated, long chain acid diglycerides and triglycerides have relatively high melting points (typically 70-77° C.). Such, fat compositions with relatively high melting points are generally more difficult to incorporate into foods, and especially if full melting is required for their incorporation. The disclosures of the '042 and '735 patents state that diglycerides with a relatively high melting point can still be incorporated into foods if combined with another fatty component, such as another diglyceride or triglyceride. These references, however, do not disclose it or how the positioning of the fatty acids on the glycerol backbone affects the properties of the fat blends. These references only indicate that the positioning of the residues in the diglycerides is not very important and provides no disclosure about fatty acid positioning in triglycerides.
As a result, there is a desire to provide a functional fat composition that can be used as a shortening or filler fat, but that has substantially reduced amounts of trans-unsaturated fatty acids, low levels of saturated fatty acids and preferably low levels of bioavailable saturated fatty acids, and a reduced caloric content.